You have 500 mL of 5 M HCl already made. You need to dilute the solution to 1 M HCl. How much water will you need to add?

You need to add 400mL of water

Explanation:

500mL = 5 M HCI     That means that if you divide both sides by 5

100mL = 1 M HCI         If you need ot get rid of 4 M HCI then you add 400 mL of water because that is what it is equal to

"among the transition metal elements, manganese and zinc have a slight lowering of electronegativities. the reason behind this is that the nuclear charges of these elements are slightly weaker than the other transition metal elements due to the way their valence electrons are filled up. both manganese and zinc have their valence electrons filled up to the 4th shell with 1 pair of electrons (4s2) completely occupying it. although the electrons in the 3rd shell (3d) are yet to be paired since the outer most shell is filled up, the ability of the nucleus to attract electrons is lessened. hence,   the electronegativity (or the ability to attract electrons) is lessened."